1. Field of the Invention
The present invention generally relates to a color filter and the manufacturing method thereof. More particularly, the present invention relates to a color filter comprising a light shielding layer formed on the black matrix of the non-display area for avoiding the light leakage from the edge area of the display and the manufacturing method thereof.
2. Description of the Related Art
As the development of the performance of computer, internet, and multimedia technology, the transformation of image information has gradually progressed from analog transformation to digital transformation. In recently years, the size and weight of many electronic device has become thin and light. As to a display device, although the conventional cathode ray tube (CRT) display is widely used, however, it has the disadvantages of large size, high radiation, heavy weight and high power consumption. Therefore, the flat panel display (FPD) is being developed having the advantages of thinner, flatter, lighter, radiation free and low power consumption, and has gradually become the mainstream of display devices. The flat panel display (FPD) including, for example, liquid crystal display (LCD), organic light emitting display (OLED) or plasma display panel (PDP).
In recent year, the liquid crystal display (LCD) is developed for the application of full-color, larger display area, higher resolution and low-cost. The color display of the liquid crystal display (LCD) is generally performed by color filters. The color filter is generally constructed over a transparent glass substrate, wherein a black matrix for light shielding, and color filter units such as red filter unit, green filter unit and blue filter unit arranged corresponding to each sub-pixel, are disposed over the transparent glass substrate. The structure of color filter will be described in detail hereinafter.
FIG. 1 is a cross-sectional view schematically illustrating the structure of a conventional color filter. Referring to FIG. 1 a color filter 100 includes a substrate 102, black matrices 104a and 104b, a plurality of color filter unit 106 and a common electrode 108. The substrate 102 includes a display area 102a in the center of the substrate 102 and a non-display area 102b surrounding the edge of the display area 102a. The black matrices 104a and 104b are disposed on the surface of the substrate 102, wherein a plurality of sub-pixel area 110 are defined by the black matrix 104a in the display area 102a, and the black matrix 104b covers the non-display area 102b that adjacent to the edge of the display area 102a. Furthermore, the color filter unit 106 is composed of a plurality of photoresists that have different colors respectively (for example, a red photoresist, a green photoresist and a blue photoresist). Each color of photoresist is disposed in the corresponding sub-pixel area 110 defined by the black matrix 104 by performing conventional photolithography, etching and developing process. Further, a common electrode 108 is further formed on the surfaces of the black matrices 104a, 104b and the color filter unit 106.
Next, referring to FIG. 1, a variety of color lights are generated by performing a white light through the color filter unit 106, wherein the black matrix 104a of the display area 102a is provided for separating the different light colors. Therefore, contrast between different light colors and the purity of each color are enhanced. Furthermore, the black matrix 104b covering the non-display area 102b adjacent to the edge of the display area 102a is provided for preventing the leakage of light from the non-display area 102b in order to enhance the image quality of the liquid crystal display (LCD).
In conventional art, the material of the black matrix generally includes chromium metal. However, use of chromium metal the black matrix is an environmental concern, and therefore some proposed to replace the chromium metal by a black resin. It is noted that, because of the light shielding effect provided by the black resin is poor compared to the chromium metal, a portion of lights will still leak out from the non-display area. Thus, the light leakage from the edge of the display area is still a problem for the color filter.